Dolomedes aquaticus is a species of fishing spider that lives and hunts along the gravel banks of unforested New Zealand rivers.

[5] The cephalothorax is chocolate brown, with a supra-marginal band of yellow extending from the posterior slope to the anterior angle of the pars cephalica: falces, maxillæ, labium, and sternum chocolate-brown; legs and palpi, brown; abdomen above greenish-brown with two longitudinal rows of brown-margined yellow spots, at the sides greyish, and below dusky-brown with four more or less continuous longitudinal whitish stripes converging towards the anus.

[5]It has been suggested that D. aquaticus is not present in the upper half of the North Island due to the lack of braided rivers in this region.

Whilst incubating, the female migrates away from the water and lives under a large stone or piece of wood.

The cocoon is globular and is carried under the sternum, to which it is firmly held by the palpi and strands of web from the spinners.